Enclosures for housing communications equipment are installed at subscriber premises to protect the connections between service provider cables and subscriber cables. One such enclosure is commonly known as a Network Interface Device (“NID”). A NID enclosure generally has electrical connectors and protection devices located in a housing that mounts to the subscriber premises. The NID connects signal transmission cables from the subscriber premises to signal transmission cables from a communications service provider, e.g. from a telephone company or cable company. The NID may also house electronic components used in connecting or dividing signals between the cables.
Typically, the housing has an outer door openable to expose an interior volume that is divided into two sections, a service provider portion (or service provider “compartment”) and a subscriber portion (or subscriber “compartment”). Often, the service provider portion is located beneath an inner door, cover, shield, or the like, while the subscriber portion is exposed simply by opening the outer door. Access to the service provider portion may require use of a specialized tool, for example to remove a fastener, such as a security nut. Thus, the subscriber can open the outer door of the housing, thereby exposing the subscriber portion of the housing to access any subscriber equipment, cabling or wiring therein. The subscriber can not, however, access the service provider portion due to the necessity of using the specialized tool to remove the security nut. Some enclosures also allow subscribers to utilize a security feature, such as a lock, that can be by-passed by the service provider. Thus, the subscriber can prevent third parties from accessing the subscriber portion of the housing, while still allowing the service provider access to both the subscriber portion and the service provider portion of the housing.
The service provider cable enters the housing through a cable port leading from the outside of the housing into the service provider portion. The service provider portion generally contains excess voltage and/or current protection devices to protect the electrical equipment from over voltages and over currents. For example, the protection devices may include fuses and/or grounding connections and wires. Electrical components and fiber optic management and routing devices, such as fan out kits, etc. belonging to the service provider may also be mounted in the service provider portion.
Similarly, the subscriber cable enters the housing through a cable port leading from the outside of the housing into the subscriber portion. The subscriber cable may include twisted wire pair cables (POTS or data), coaxial cables (television or data), and even fiber optic cables. Various terminations may be provided in the subscriber portion to allow the NID to be used with different subscriber communications equipment. A subscriber bridge, also referred to as a line module, may be used and is at least partially located within the subscriber portion so as to be accessible by the subscriber. Such a subscriber bridge has one or more subscriber line terminal blocks connected with the subscriber cable. The subscriber bridge may also have a telephone jack providing a demarcation between the subscriber line and the service provider line for directly accessing the service provider line.
In many conventional installations, the service provider cable and the subscriber cable comprise twisted wire pairs. Because some NIDs have provisions for accommodating service provider coaxial cables and/or fiber optic cables, active electronic components have been developed that can receive several signals on such service provider cables and separate the signals into a variety of subscriber outputs, such as voice, internet, and video (e.g., television). These active electronic components are typically mounted on a printed circuit board (PCB), which in the past has been mounted behind the enclosure. In such NIDs, the entire housing has to be removed from the building to gain access to the PCB. As a result, installing and servicing the active electronic components is time consuming. Other designs have been successfully deployed wherein the active electronic components are mounted in the service provider portion of the housing, either attached to the base of the housing, or attached to the internal cover that separates the service provider portion from the subscriber portion.
NIDs may be grounded via a ground line that directs excess voltage, for example in case of lightning strike, away from the housing to protect the electrical equipment and devices connected to the service provider and subscriber cables. Therefore, various cables and components within the NID may be individually attached to a common (earth) ground line as needed. The earth ground line may be attached to a grounding post within the NID. A ground lug may be provided on the PCB and grounding post for making the connections, for example via a short jumper wire or other conductor connecting the PCB to the grounding post and ground line. If the PCB is mounted on or within an inner cover separating the service provider portion and the subscriber portion, the PCB ground connection may need to be disconnected each time the inner cover is to be opened, even if the PCB itself is not being serviced. Further, upon closing of the NID, the technician must remember to connect, or reconnect as the case may be, the ground to the PCB via the jumper wire or conductor, before securing the inner cover. As the contents of the NID become more complex, the number of grounding connections needed are accordingly increased, adding cost and complexity to the device, and adding additional steps to installation or servicing the NID. Therefore, further improvement is desirable in providing a grounded enclosure that is reliable and/or simplifies the conventional grounding structures or procedures.
NIDs are generally mounted via mounting feet to a vertical wall, often by screws extending through the mounting feet. One or more cable ports typically extend from a side of the NID housing, usually the bottom, to allow the various service provider and subscriber cables to enter the housing. As stated above, the service provider usually intends that only certain portions of the housing be accessible to the subscriber. For obvious reasons, service providers want to discourage subscribers from attempting to disturb the service provider portion of the housing, for example, by trying to force open an access door to the service provider compartment, by disconnecting mounting screws, or by trying to manipulate cabling by pulling on the cables entering the housing through the cable ports. Accordingly, service providers have fashioned NIDs with specialized security features, such as security nuts, outer covers, selectable locking, and clear labeling to alert the subscriber as to how and where to open the housing to obtain access to the subscriber portion. However, still further improvement could be achieved in preventing unauthorized or unintended access to the service provider portion, while also providing an aesthetically pleasing NID housing design.